The present invention relates to novel pyrazolo[3,4-d]pyrimidinone compounds, capable of inhibiting the interaction between p53, or variants thereof, and MDM2 and/or MDM4, or variants thereof, respectively, especially binding to MDM2 and/or MDM4, or variants thereof, a process for the preparation of such compounds, pharmaceutical preparations comprising such compounds, uses and methods of use for such compounds in the treatment (including therapy and/or prophylaxis), and/or related subject matter as specified below. p53 refers to all genes and/or proteins encoded thereof with the names TP53, p53, TP73, p73, TP63, TP73L, p63. MDM2 refers to all genes and/or proteins encoded thereof with the names MDM2, Mdm2, HDM2, Hdm2. MDM4 refers to all genes and/or proteins encoded thereof with the names MDM4, Mdm4, HDM4, Hdm4, MDMX, MdmX, HDMX, HdmX.
Protein p53 is known as a tumor suppressor protein which helps to control cellular integrity and prevents the proliferation of permanently damaged cells by initiating, among other responses, growth arrest or apoptosis (controlled cell death). p53 mediates its effects in that it is a transcription factor capable of regulating a number of genes that regulate e.g. cell cycle and apoptosis. Thus, p53 is an important cell cycle inhibitor. These activities are tightly controlled by MDM2, an important negative regulator of the p53 tumor supressor. “MDM2” (originally from the oncogene “murine double minute 2”) refers both to the name of the gene as well as the protein encoded by that gene. MDM2 protein functions both as an E3 ubiquitin ligase that recognizes the N-terminal trans-activation domain (TAD) of the p53 tumor suppressor and thus mediates the ubiquitin-dependent degradation of p53, and as an inhibitor of p53 transcriptional activation.
The original mouse oncogene, which codes for the MDM2 protein, was originally cloned from a transformed mouse cell line. The human homologue of this protein was later identified and is sometimes also called HDM2 (for “human double minute 2”). Further supporting the role of MDM2 as an oncogene, several human tumor and proliferative disease types have been shown to have increased levels of MDM2, including inter alia soft tissue sarcomas, bone cancer, e.g. osteosarcomas, breast tumors, bladder cancer, Li-Fraumeni syndrome, brain tumor, rhabdomyosarcoma and adrenocortical carcinoma and the like. Another protein belonging to the MDM2 family is MDM4, also known as MDMX.
Dysregulation of the MDM2/p53 ratio, e.g. due to mutations, polymorphisms or molecular defects in the affected cells, can thus be found in many proliferative diseases. MDM2, in view of its mentioned effects, is capable to inhibit the activity of the tumor suppressor protein p53, thus leading to loss of p53's tumor suppressor activity and inhibiting regulatory mechanisms that impede cells from uncontrolled proliferation. As a consequence, uncontrolled proliferation can take place, leading to cancers such as tumors, leukemias or other proliferative diseases.
WO2011/076786 discloses isoquinolinone and quinazolinone compounds as inhibitors of the interaction between p53 and MDM2 and/or 4.
There is a need for new drugs that are capable of interfering with the interaction between p53 and MDM2 or especially oncogenic variants thereof and that thus allow p53 to exert its beneficial effect against uncontrolled tumor growth, allowing it e.g. to accumulate, to arrest the cell cycle and/or to cause apoptosis of affected cells.
It has now been found that a novel class of pyrazolo[3,4-d]pyrimidinone compounds shows inhibition of the MDM2/p53 and/or MDM4/p53 interaction (this term including in particular Hdm2/p53 and Hdm4/p53 interaction), and in particular potent inhibition of the MDM2/p53 interaction. The corresponding compounds thus represent a novel type of compound that are useful in the treatment of a number of disorders, such as proliferative diseases, especially cancer. The invention relates therefore to these compounds as drugs as well as to the other inventive embodiments indicated herein.